(define (make-interval a b)
    (cons a b)
)
(define (lower-bound z)
    (car z)
)
(define (upper-bound z)
    (cdr z)
)

(define (print-interval x)
    (newline)
    (display "[")
    (display (lower-bound x))
    (display ",")
    (display (upper-bound x))
    (display "]")
)


(define (sub-interval x y)
    (make-interval 
        (- (lower-bound x) (lower-bound y))
        (- (upper-bound x) (upper-bound y))
    )
)

(define interval_1 
    (make-interval 2 3)
)

(define interval_2 
    (make-interval 1 2)
)
(print-interval (sub-interval interval_1 interval_2))
(exit)

(exit)
